Blowing device for rock drills



Nov.`26, '1929; w. A. SMITH, JR 1,736,864.

BLOWING DEVICE FOR ROCK DRILLS Filed Deo. 14, 1928 dal INVENTOR. Wiliam mifk rf BY HIS/1L TORNEY.

Patented Nov. 26, 1929 UNITED STATES was@ PATENT WILLIAM A. SMITH, JR., OF PHILLIPSBURG, NEW JERSEY, ASSIGNOR T0 INGERSOLL-*U RAND COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEVJ JERSE BLOWING DEVICE FOR ROCK DRILLS Application led December 14, 1928.

This invention relates to rock drills, but more particularly to a blowing device for fluid actuated rock drills of the hammer type.

One object of the invention is to selectively admit an uninterrupted flow of pressure fluid through the rock drill and the drill steel into the drill hole for blowing the cuttings therefrom.

Another object is to maintain the distributing valve firmly seated in the valve chamber during the blowing operation unaffected by any pressure fluid which may exert a force thereon tending to unseat the valve during the blowing operation.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawings illustrating the invention and in which similar reference characters refer to similar parts,

Figure l is a sectional elevation of a portion of a rock drill having the invention applied thereto,

Figure 2 is a transverse view taken through Figure l on the line 2 2 looking in the direction indicated by the arrows, and

Figure 3 is a view similar to Figure l showi ing a modified form of the invention.

Referring to the drawings, A represents a cylinder of a rock drill having a piston chamber B inv which is disposed a reciprocatory hammer piston C for delivering blows of 1mpact to a working implement (not shown). The piston C carries at its front end an extension D which extends slidably through a bore E of a front cylinder washer F disposed in the front end of the cylinder A to form a closure therefor. The extension D is provided with the usual flutes G to slidably interlock with chuck mechanism (not shown) in a well known manner for rotating the working implement.

The cylinder A has an exhaust port H which is normally controlled by the piston Serial No. 325,986.

head O at the rearward end ofthe cylinder A.

The rotation ratchet L has introverted teeth P to act as abutments for spring pressed pawls Q, carried by the head R of a rifleb-ar S to impart a stepA by step rotary motion tol the piston C wherewith the rifle bar S is slidably interlocked. Y v` j The admission of pressure fluid into the drill is controlled by a throttle valve T seated in the back head O and having a .lever U whereby the throttle valve T may be rotated. The pressure fluid may be conveyed to the drill by a suitable conduit (not shown) from a source of supply and is intended to beadmitted into a central chamber V of thegthrottle valve T wherewith it may be in constant communication. In the side of the throttle valve T is a port W which, in the open position of the throttle valve T, registerswith a passage X leading to a supply reservoir Y' in the forward end of the back head O.

From the supply reservoir Y the pressure fluid flows through supply passages Z in the rotation ratchet L into a valve chamber b`,`in this instance of annular form, and formed in the front end of the rotation ratchet L.

The valve chamber ZJ communicates with the front and rearward ends of the piston chamber B Vthrough inlet passages c and l respectively. The inlet passage d opens directly into the rearward end of the piston chamber B and the inlet passage c is formed in the back cylinder washer K and in the' wall of the cylinder A and opens into the front end of the piston chamber. y

The means whereby the distribution of pressure fluid to the ends of the pistonv chamber B is effected consists in this instance of an oscillatory plate type valve e in the form of a ring yand having a fulcrum f on its transverse median line whereon saidvalve is adapted to rock from one limiting position to another. The valve e thus has wings g and t on opposite sides of thefulcrum f which controls the inlet passages el and 0 respectively.

During the normal' operation of the parts of the drill so far described the flutesy G of the piston extension D will be drawn into the forward end of the piston chamber B upon each rearward stroke of the piston and a portion of the pressure fluid utilized for actuating the piston C rearwardly will flow through said flutes and through the forward part of the drill into the working implement and into the drill hole for removing the cuttings therefrom.

Under certain conditions the amount of fluid admitted into the drill hole in this manner. may suffice to maintain the drill hole fairlyclean. There are conditions, however, where this method of cleansing the drill hole has been found inadequate as the cuttings accumulate more rapidly than they can be removed from the drill hole. Then this occurs the dust and broken rock particles will be moved rearwardly of the cutting bit around which'they form a collar and, due to the in* creased friction on the rock greatly interfere with the action of the drill,

It is desirable that the cuttings in most drilling operations should be removed as rap-4 idly as they are formed and to this end means are provided in the present instance to effect a thorough cleansing of the drill hole whenever the ordinary means provided for this purpose are found to be inadequate. Accord ingly the cylinder A is provided with a throttle valve chamber j which extends transversely through the exhaust port I-I for the reception of a blower valve 70, shown in this instance as being of the rotatable type and having a lever Q'whereby it may be rotated fromthe open to the closed position7 and vice versa.

In one side of the blower valve 7c is a recess pwhich, in the open position of the blower valve, will permit the free escape of pressure fluid through the exhaust port H during the normal operation of the drill.

By-using the flutes G in the piston extension'D as channels for conveying the pressure fluid from the piston chamber' to the working implementpressure fluid should enter only theffront end of the piston chamber, and to accomplish this result the valve e should of course remain immovable in the valve chamber so that pressure lluidrrnay flow only over one end thereof, in this instance over the end h. t

OrdinarilyA during blowing and when distributing valves of the typeillustrated are used there is some tendency for the pressure fluid flowing over the raised end of the valve to exert a` force thereont-ending tovraise the opposite or seated end of the valve. This admits pressureV fluid in small'quantities into the rearward end of the piston chamber and tends to move the piston C into a position in which the flutes G will lie entirely within the bore E of the front cylinder washer, thus cutting off the supply of pressure fluid to the working implement. Means are accordingly provided to assure the retention 'of the distributing valve e in the positionl which it should occupy during the blowing operation. To this end a passage g is formed in the back cylinder washer K and in the cylinder A to open with one end into a cavity 1" in the back cylinder washer K at a point near the inlet passage d and directly beneath the4 wing g of the valve e sotthat when the end g of the valve e is seated on the 'back cylinder washer K the cavity r will be completely covered by the valve. v L

Theopposite end ofthe assage g opens into the throttle valve cham er and regis ters with a port-8 in the blower valve 7c in the closed position of the blower valve. The port s extendsAv through the blower valve lc and opens into the outlet opening of the exhaust port H. s In this way 'when the blower valve Za is closed'the cavity r will be in direct communication with the atmosphere.

In order to create aV vacuum in the cavity r while blowing is taking place the back cylin der washer AK is provided with a port t which has its inlet opening outside of the edge of the valve e and opens with its other end into the passage g so that when the blower valve 7c is closed: pressure fluid may flow from the valve chamber b through the port t into the passage g and create a sub-atmospheric pressure in the cavity r which will tend to 'main-V tain the end g of thevalve firmly seated ou the baclrcylinderwasherK.

,The operation of the device is as follows: Let it be assumedthat the drill is operating in the normal manner7 that is,'t he piston C is delivering its blow againsty the working im;l plement. If then, the cuttings in the drill hole accumulate to anextent which will render the ordinary blowing means for removing the cuttings ineffective, the blower valve 7c may be closed to prevent the escape of fluid from the piston chamber.

In the closed position of the blower valve 7c the passage Q will be open to the atmosphere through the ports inthe blower valve and the valve end g will then seat onthe back cylinder` washer K so that the pressure fluid may flow over the end 7g, of the valve e through the inlet passage 0 into theV front end of the piston chamber to move the piston C rearwardly a sufficient distanceto hold the flutes Gr in come..

munication withthe frontend of the piston chamber. Pressure fluid will then escape through the flutes and through the front part of the drill into the drill steel'and into the drill hole and will blow the cuttings there;A from. Y l

Durino` the blowing of thedrill' hole pressure fluid will be constantly flowing from the valvechamber l through the port t into the Vpassage .g and will create a vacuum in thecavity r which'will assist in maintaining the end g of the valve firmly seated on the back cylinder washer This will stabilize the valve e during the blowing operation. After the hole has been cleansed the blower valve la..

may be rotated to the open position and normal drilling will then again be resumed.

In the open position of the throttle valve the recess p will establish communication between the piston chamber B and the exhaust port H, and the outlet opening of the passage q will be closed by the blower valve la so that the distributing valve e may then operate in a normal manner for distributing the pressure fluid to the ends of the piston chamber B.

The modied form of the invention illustrated in Figure 3 is in most respects like that described in connection with the preferred modification. In this instance the drill is also provided with a passage g which leads from the cavity 1' to the exhaust port H and a port u is formed in the wing g of the valve e to introduce pressure fluid into the passage g for creating the sub-atmospheric pressure therein to hold the end g of the valve firmly seated during the blowing operation.

I claim:

1. In a fluid actuated rock drill, the combination of a cylinder and a piston having a fluted extension, an exhaust port in the cylinder, a valve chamber, inlet passages leading from the valve chamber to the cylinder, a distributing valve in the valve chamber controlling the inlet passages, a blower valve for closing the exhaust port to arrest the movement of the distributing valve thus causing pressure fluid to flow through only one inlet passage into the cylinder and through the flutes in the piston extension, a passage leading from the valve chamber to the exhaust port and controlled by the valve, and a port injecting pressure fluid from the valve chamber through the passage to create a vacuum in a portion of the valve chamber tending to maintain the distributing valve firmly seated during the blowing operation.

2. In a fiuid actuated rock drill, the combination of a cylinder and a piston, a fluted extension on the piston, an exhaust port in the cylinder, a valve chamber, inlet passages leading from the valve chamber to the cylinder, an oscillatory plate valve having a pair of wings to control the inlet passages, a passage leading from one end of the valve chamber to the exhaust port, a blower valve for closing the' exhaust port to arrest the movement of the plate valve thus causing pressure fluid to fiow through an inlet passage into one end of the cylinder and through the flutes in the extension, and a port for conveying pressure fluid from the valve chamber into the passage to create a vacuum beneath the seated end of the plate valve to hold said plate valve firmly seated during the blowing operation.

3. In a fluid actuated rock drill, the combination of a cylinder and a piston, a fluted extension on the piston, an exhaust port in the cylinder normally controlled by the piston, a valve chamber, inlet passages leading from the valve chamber to the cylinder, an oscillatory plate distributing valve having a pair of wings to control the inlet passages, a passage opening at one end into the exhaust port and with its other end in the valve chamber beneath one wing of the valve, a blower valve for closing the exhaust port to arrest the movement of the distributing valve thus causing pressure fluid to flow through only one inlet passage into the cylinder and through the flutes in the extension, and a port for conveying pressure fiuid from the valve chamber into the passage for creating a vacuum beneath the seated end of the valve to hold said valve firmly seated during the blowing operation.

4. In 'a fluid actuated rock drill, the combination of a cylinder and a piston, a fluted extension on the piston, an exhaust ort in the cylinder normally controlled by t e piston, a valve chamber, inlet passages leading from the valve chamber to the cylinder, an oscillatory plate distributing valve having a pair of wings to control the inlet passages, a passage opening at one end into the exhaust port and with its other end in the valve chamber beneath one wing of the valve, a blower valve for closing the exhaust port to arrest the movement of the distributing valve thus causing pressure fluid to blow through one inlet passage into the front en d of the cylinder and through the flutes in the extension, a port for conveying pressure fluid from the valve chamber into the passage for creating a vacuum beneath the seated end of the distributing valve to hold said valve firmly seated during the blowing operation, and a port in the blower valve affording communication between the passage and the atmosphere in the closed position of the blower valve.

In testimony whereof I have signed this specification.

WILLIAM A. SMITH, JR. 

